Belt type sanding machine



March 29, 1960 H. D. OSLUND BELT TYPE SANDING MACHINE Filed Sept. 25, 1957 INVENTOR. HERBERT D. OSLUND ATTORNEY United States Patent BELT TYPE SANDING MACHINE Herbert D. Oslund, Minneapolis, Minn. Application September 25, 1957, Serial No. 686,099

2 Claims. (Cl. 51-141 This invention relates broadly to power tools; more particularly, to an electric powered sanding tool; and specifically to a powered stationary belt sander. While the invention is illustrated herein as a complete unit including an electric motor, it will be understood that the invention is capable of being supplied as an independent unit and mounted for use with existing power equipment, i.e. the electric motor. 7

The principal object of the invention is to provide a belt type sanding machine that is highly efiicient, relatively inexpensive to manufacture and completely safe in operation.

Another object of this invention is to provide a belt type sanding machine that may readily be adapted for use with already existing power equipment.

Another object of this invention is to provide a belt .type sanding machine in which there are relatively few moving parts and wherein its adjustment are relativel few and readily accessible.

Another object of this invention is to provide a belt type sanding machine embodying an extremely efiicient system of belt interchangeability and tensioning.

These and other objects of this invention will become apparent from the following specification and claims, taken in conjunction with the appended drawing which forms a part of this invention and in which like characters indicate like parts throughout the several views.

To the above end, generally stated, the invention consists of the novel devices and combination of devices hereinafter described and defined in the claims.

Referring to the drawings:

' Fig. 1 is a front 'elevational view of the invention mounted on a base with an electric motor as a single unit;

Fig. 2 is a rear elevational view of the same;

Fig. 3 is a sectional view of the belt tensioning mechanism on an enlarged scale;

Fig. 4 is a side elevational view; and

Fig. 5 is a side elevation of a combined dust hopper and belt guard, also on an enlarged scale.

In the interest of clarity and to keep the specification in conformity with the drawing, I shall for the purpose of this application treat the invention as a unitary assembly wherein the sanding mechanism and the power source therefor are mounted on a common base as an entirety. It is to be understood, however, that the invention described and claimed herein is capable of independent mounting with independent power sources, independently mounted on a suitable base with driving connections between said power source and the sanding machine.

The numeral 6 indicates a relatively shallow, substantially square base and the numeral 7 is directed to a conventional type of electric motor attached to the base 6 by bolts 8 and having a single extension of its armature shaft, not shown, for purposes that will presently be explained.

A heavy upstanding forwardly inclined bracket 9 has a pair of outturned flanges 10 forming its lower end portion to afford a solid mount for attaching the bracket 9 to the base 6 which, as shown, is accomplished by two pair of nut-equipped screw-threaded bolts 11, which extend through aligned bores in the bracket 9 and the base 6. A vertically disposed stiffening member 10' is' formed integral the bracket 9 and one of its base flanges 10 at right angles to the vertical plane of the bracket 9. .The bracket 9 is mounted on said base somewhat rearwardly of the horizontal axis of the electric motor.

A heavy metal relatively wide, transversely, platen or work table 12, having a depending mounting flange 13 that extends along the inner longitudinal edge portion of the platen 12 to substantially the longitudinal center thereof, is rigidly mounted on a rearwardly inclined plane at'the diagonally angled upper edge portion of the upstanding bracket 9 by means of screw-threaded studs 14 which extend through bores 15 in the bracket 9 and engage tapped and threaded bores 16 in the depending flange 13 of the platen 12. The rigidly connected bracket 9 and the platen 12 are somounted on the base 6 that the'lower end portion of the upwardly and rearwardly inclined platen 12 overlies with ample clearance the axis of the armature shaft of the electric motor 7. Mounted on the extension of the said armature shaft, not shown, is a relatively Wide fast roller type driven pulley 17 that is held against axial rotation on the said extension of the armature shaft of the motor 7 by means of Allen screws, not shown, or by keying said pulley to said shaft. It is important to note here that the electric motor 7 and the pulley 17 mounted on the armature shaft thereof are mounted on the base 6 relative to the bracket 9 and its mounted platen 12 in such a manner that the pulley 17 and the platen 12 are in lateral alignment. It is also important to note that the inclined plane of the platen 12, if projected downwardly and rearwardly, would cross the periphery of the roller pulley 17 with slight clearance.

. For purposes that will become apparent, it is important that the upper surface of the platen 12 is relatively smooth or even polished and that'the end portions thereof are angularly beveled or machined smooth on a radius, see numeral 18. I

Mounted or cast integral with the platen 12 on the under surface thereof, adjacent its upper end portion, and laterally extending outwardly of each longitudinal edge portion of said platen, are a pair ofheavy lugs 19 each having a tapped and threaded bore 19, said bores being in a plane with the longitudinal axis of the platen 12.

An adjustable mounting bracket 20 has a longitudinally disposed base portion 20 and a pair of upturned lugs or ears 21 each having axially aligned bores 22, affords a mounting station for a driven roller type pulley 23 that is mounted fast on a short shaft 24 which is journaled in the respective bores 22 in the lugs or ears 21. A pair of Allen screws or key means, not shown, hold the pulley 23 against endwise movement on the shaft 24 and similarly holds the said shaft against endwise movement in the bores 22. Bushings or oilless bearings 25 of any suitable material are fitted to each of the bores 22.

A relatively long and heavy lug 26 depends from the base portion 20 of the bracket 20 flush with the inner longitudinal edge portion of said base portion 20' and is transversely dimensioned for endwise movements in a plane with the angularly disposed platen 12, between the lugs 19 on the underside of the platen 12 which act as guides for the depending lug 26 of the bracket 20. The lug 26 is provided with an elongated slot 27, and a screw-threaded washer-equipped stud 28 extends through.

memes to protrude above the upper surface thereof when drawn tight to rigidly hold the bracket 20 against endwise movement from a predetermined position as determined by the length of the sanding belt and adjustment of the pulley 23, as will presently appear.

A pair of long screws 30 having any suitable head for manual adjustment by tool or fingers have engagement with the screw threads in the bores 19 of the lugs 19 and extend through said lugs from their under surface to engage the under surface of the base portion 20' of the adjustable bracket or pulley mount 20. These screws 30, acting on each side of the bracket 20 at the base thereof, afford micrometer-like adjusting means for maintaining adjustment of the upper pulley 23 and, similarly, the adjustment and tension of a sanding belt 31 which runs between the driver pulley 17 and the driven pulley 23 and in its upper nin, over the upper surface of the platen 12 which acts as a base of resistance for work being held to the abradant surface of the running belt 31.

It will be understood that the pulleys 17 and 23, the platen 12, and the belt 31 are all of the same approximate width.

A work rest 32 in the form of an L-shaped bracket is pivotally mounted at its left-hand side to the bracket 9 by means of a washer-equipped and headed screwthreaded stud 33. This stud 33 has threaded engagement with a tapped and threaded bore that extends into the bracket 9 and the flange 13 and is adjustable relative to the platen 12 over which it extends transversely.

A dust guard plate 34 is interposed between the motor 7 and the lower end portion of the bracket 9.

A dust hopper 35 is so mounted as to surround the lower run of the belt 31 and further serves as a guard to keep the fingers and clothing from easy contact with the lower driver pulley 17 and the running belt 31 when the machine is in operation.

As shown, the hopper 35 is mounted on the base 6 and surrounds the pulley 17 and the lower end run of the belt .31. A hanger member 36 connecting the hopper 35 to the bracket 9 by means of screw-threaded nut-equipped bolts 37 afiords a simple means by which the hopper may be readily detached for cleaning.

To further overcome the problem of dust during the operation of the machine, I provide an outlet port 38 in the rear end portion of the hopper 35 that is constructed to receive the attachment coupling of a conventional vacuum cleaner. Thus when the sanding device is in operation, particularly for extended periods of time, such a cleaner may be attached and operated simulta- 4 neously to dispose of the dust almost as rapidly as it collects in the hopper 35.

While the preferred embodiments of the invention are disclosed herein it should be understood that modifications can be made within the scope of the appended claims without departing from the scope of the invention.

What I claim is:

l. A stationary power sanding machine of the belt type comprising in combination, a base, an upright support member mounted on said base, an ofiset upwardly and rearwardly inclined platen mounted on and at right angles to the vertical plane of said upright support member, an endwise adjustable mounting bracket on the upper end portion of said platen affording a mounting station for a driven pulley horizontally mounted for rotation in the plane of the upper surface of said platen, guide and locking means on the under surface of the said platen associated with said adjustable bracket, a pivotally mounted'work support arm on the upright support member extending transversely above and across said platen, an electric motor mounted on the base, an outwardly extended armature shaft on said motor affording a mounting station for a driver pulley mounted on said armature shaft extension for rotation therewith, said driver pulley and driven pulley and the platen being in longitudinal alignment on an upwardly and rearwardly inclined plane and an endless sanding belt arranged to run over said pulleys, and the platen on the upper run of said belt, said platen affording a base of resistance for work held to the running sanding belt.

2. The structure defined in claim 1, further including a dust gathering hopper detachably mounted on said base and the upright support member, said hopper substantially surrounding the driver pulley and the lower run of the sanding belt.

References Cited in the file of this patent UNITED STATES PATENTS 296,535 Coy Apr. 8, 1884 812,317 Wysong Feb. 13, 1906 833,726 Bein Oct. 23, 1906 860,367 Gramelspacher July 16, 1907 947,491 Bein Ian. 25, 1910 953,031 Hausman et a1. Mar. 29, 1910 968,726 Wysong Aug. 30, 1910 1,594,445 Blevncy Aug. 3, 1926 2,513,449 Caldwell July 4, 1950 2,791,070 Schaller -3. May 7, 1957 

